public static void ConvertHtmlToPdf(PdfDocument document, PdfConvertEnvironment environment, PdfOutput woutput)
        {
            if (environment == null)
                environment = Environment;

            String outputPdfFilePath;
            bool delete = false;
            if (woutput.OutputFilePath != null)
                outputPdfFilePath = woutput.OutputFilePath;
            else
            {
                outputPdfFilePath = Path.Combine(environment.TempFolderPath, String.Format("{0}.pdf", Guid.NewGuid()));
                delete = true;
            }

            if (!File.Exists(environment.WkHtmlToPdfPath))
                throw new PdfConvertException(String.Format("File '{0}' not found. Make sure wkhtmltopdf files exist.", environment.WkHtmlToPdfPath));

            var paramsBuilder = BuildParameters(document, outputPdfFilePath);

            var si = new ProcessStartInfo
                {
                    CreateNoWindow = !environment.Debug,
                    FileName = environment.WkHtmlToPdfPath,
                    Arguments = paramsBuilder.ToString(),
                    UseShellExecute = false,
                    RedirectStandardError = !environment.Debug
                };

            try
            {
                using (var process = new Process())
                {
                    ProcessHtmlToPdf(si, process, environment, document);

                    if (!File.Exists(outputPdfFilePath))
                        throw new PdfConvertException(String.Format("Html to PDF conversion of '{0}' failed. Reason: Output file '{1}' not found.", document.Url, outputPdfFilePath));

                    WriteOutput(woutput, outputPdfFilePath);
                    ExecuteCallback(document, woutput, outputPdfFilePath);
                }
            }
            finally
            {
                if (delete && File.Exists(outputPdfFilePath))
                    File.Delete(outputPdfFilePath);
            }
        }
        private static void ProcessHtmlToPdf(ProcessStartInfo si, Process process, PdfConvertEnvironment environment, PdfDocument document)
        {
            process.StartInfo = si;
            process.Start();

            if (!process.WaitForExit(environment.Timeout))
                throw new PdfConvertTimeoutException();
            if (process.ExitCode != 0)
            {
                var error = si.RedirectStandardError ? process.StandardError.ReadToEnd() : String.Format("Process exited with code {0}.", process.ExitCode);
                throw new PdfConvertException(String.Format("Html to PDF conversion of '{0}' failed. Wkhtmltopdf output: \r\n{1}", document.Url, error));
            }
        }